![Johannes Berg](/assets/img/avatar_default.png)
There's no need to use a single scratch buffer and calculate offsets into it, just use two separate buffers for the separate variables. Signed-off-by: Johannes Berg <johannes.berg@intel.com>
129 lines
2.6 KiB
C
129 lines
2.6 KiB
C
/*
|
|
* AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
|
|
* Copyright 2008, Jouni Malinen <j@w1.fi>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/crypto.h>
|
|
#include <linux/err.h>
|
|
#include <crypto/aes.h>
|
|
|
|
#include <net/mac80211.h>
|
|
#include "key.h"
|
|
#include "aes_cmac.h"
|
|
|
|
#define AES_CMAC_KEY_LEN 16
|
|
#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
|
|
#define AAD_LEN 20
|
|
|
|
|
|
static void gf_mulx(u8 *pad)
|
|
{
|
|
int i, carry;
|
|
|
|
carry = pad[0] & 0x80;
|
|
for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
|
|
pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
|
|
pad[AES_BLOCK_SIZE - 1] <<= 1;
|
|
if (carry)
|
|
pad[AES_BLOCK_SIZE - 1] ^= 0x87;
|
|
}
|
|
|
|
|
|
static void aes_128_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
|
|
const u8 *addr[], const size_t *len, u8 *mac)
|
|
{
|
|
u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
|
|
const u8 *pos, *end;
|
|
size_t i, e, left, total_len;
|
|
|
|
memset(cbc, 0, AES_BLOCK_SIZE);
|
|
|
|
total_len = 0;
|
|
for (e = 0; e < num_elem; e++)
|
|
total_len += len[e];
|
|
left = total_len;
|
|
|
|
e = 0;
|
|
pos = addr[0];
|
|
end = pos + len[0];
|
|
|
|
while (left >= AES_BLOCK_SIZE) {
|
|
for (i = 0; i < AES_BLOCK_SIZE; i++) {
|
|
cbc[i] ^= *pos++;
|
|
if (pos >= end) {
|
|
e++;
|
|
pos = addr[e];
|
|
end = pos + len[e];
|
|
}
|
|
}
|
|
if (left > AES_BLOCK_SIZE)
|
|
crypto_cipher_encrypt_one(tfm, cbc, cbc);
|
|
left -= AES_BLOCK_SIZE;
|
|
}
|
|
|
|
memset(pad, 0, AES_BLOCK_SIZE);
|
|
crypto_cipher_encrypt_one(tfm, pad, pad);
|
|
gf_mulx(pad);
|
|
|
|
if (left || total_len == 0) {
|
|
for (i = 0; i < left; i++) {
|
|
cbc[i] ^= *pos++;
|
|
if (pos >= end) {
|
|
e++;
|
|
pos = addr[e];
|
|
end = pos + len[e];
|
|
}
|
|
}
|
|
cbc[left] ^= 0x80;
|
|
gf_mulx(pad);
|
|
}
|
|
|
|
for (i = 0; i < AES_BLOCK_SIZE; i++)
|
|
pad[i] ^= cbc[i];
|
|
crypto_cipher_encrypt_one(tfm, pad, pad);
|
|
memcpy(mac, pad, CMAC_TLEN);
|
|
}
|
|
|
|
|
|
void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
|
|
const u8 *data, size_t data_len, u8 *mic)
|
|
{
|
|
const u8 *addr[3];
|
|
size_t len[3];
|
|
u8 zero[CMAC_TLEN];
|
|
|
|
memset(zero, 0, CMAC_TLEN);
|
|
addr[0] = aad;
|
|
len[0] = AAD_LEN;
|
|
addr[1] = data;
|
|
len[1] = data_len - CMAC_TLEN;
|
|
addr[2] = zero;
|
|
len[2] = CMAC_TLEN;
|
|
|
|
aes_128_cmac_vector(tfm, 3, addr, len, mic);
|
|
}
|
|
|
|
|
|
struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[])
|
|
{
|
|
struct crypto_cipher *tfm;
|
|
|
|
tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
|
|
if (!IS_ERR(tfm))
|
|
crypto_cipher_setkey(tfm, key, AES_CMAC_KEY_LEN);
|
|
|
|
return tfm;
|
|
}
|
|
|
|
|
|
void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm)
|
|
{
|
|
crypto_free_cipher(tfm);
|
|
}
|